Excavation based enhanced geothermal system (EGS-E): introduction to a new concept

  • J. ZhaoEmail author
  • C. A. Tang
  • S. J. Wang
Original Article
Part of the following topical collections:
  1. Sustainable development and utilization of geothermal systems


The current technology for enhanced geothermal system (EGS) typically involves drilling of deep injection and production wells to inject cold water into the injection well to the EGS reservoir depth, to extract heat by permeating through the fractured hot rock masses, collected by the production well and return to the surface as heated water. In this article, a new approach is proposed to develop EGS based excavation technology (EGS-E). This method consists of (1) excavation to deep rocks, including a deep shaft from surface to the EGS depth, a room-and-pillar mined cavern complex to be filled with water to become a large underground heated water reservoir in the hot rocks; (2) enhanced heat extraction from rock, aided by additional drillholes spreading out and down from the caverns, and induced fracturing of the surrounding rocks for enhanced rock–water heat transfer; (3) enclosed heat transmission from heated water reservoir to the power plant by using independent heat conducting pipes running between them, continuously supplying the heat for power generation, without water movement in the reservoir. EGS-E offers the following advantages: (1) utilizing mechanized rock excavation technology for large volume energy production; (2) greatly increasing heat extraction volume by easily extending vertically and horizontally; (3) maximize the energy transfer from hot rock to the water reservoir; and (4) separated heat transmission from heated water reservoir in EGS to power plant to minimize environmental pollution.


Enhanced geothermal system (EGS) Deep rock excavation Hot water reservoir Hot dry rock Heat transfer 



  1. Bahadori A, Zendehboudi S, Zahedi G (2013) A review of geothermal energy resources in Australia: current status and prospects. Renew Sustain Energy Rev 21:29–34CrossRefGoogle Scholar
  2. Baria R, Baumgärtner J, Gérard A, Jung R, Garnish J (2002). European HDR research programme at Soultz-sous-Forêts (France); 1987–1998. In: Baria R, Baumgärtner J, Gérard A, Jung R (eds) International conference—4th HDR Forum (September 28–30, 1998: Strasbourg, France), Geologisches Jahrbuch special edition. Hannover, Germany, pp 61–70Google Scholar
  3. Batchelor AS (1984) Hot dry rock geothermal exploitation in the United Kingdom. Mod Geol 9:1–41Google Scholar
  4. Bertani R (2012) Geothermal power generation in the world 2005–2010 update report. Geothermics 41:1–29CrossRefGoogle Scholar
  5. Breede K, Dzebisashvili K, Liu X, Falcone G (2013) A systematic review of enhanced (or engineered) geothermal systems: past, present and future. Geotherm Energy 1(4):1–27Google Scholar
  6. Brown DW (1993). Recent flow testing of the HDR reservoir at Fenton Hill, New Mexico. Geothermal Program Review XI, April, 1993. U.S. Department of Energy, Conservation and Renewable Energy, Geothermal Division, pp 149–154Google Scholar
  7. Brown DW (1995) The US hot dry rock program—20 years of experience in reservoir testing. In: Proceedings of the world geothermal congress (May 18–31, 1995: Florence, Italy), vol 4. International Geothermal Association, Inc., Auckland, New Zealand, pp 2607–2611Google Scholar
  8. Brown DW (2009). Hot dry rock geothermal energy: Important lessons from Fenton Hill. In: Proceedings, 34th workshop on geothermal reservoir engineering (February 9–11, 2009: Stanford, CA). SGP-TR-187, pp 139–142Google Scholar
  9. Chamorro CR, García-Cuesta JL, Mondéjar ME, Pérez-Madrazo A (2014) Enhanced geothermal systems in Europe: an estimation and comparison of the technical and sustainable potentials. Energy 65:250–263CrossRefGoogle Scholar
  10. Chopra P, Wyborn D (2003). Australia’s first hot dry rock geothermal energy extraction project is up and running in granite beneath the Cooper Basin, NE South Australia. In: Proceedings, the Ishihara symposium: granites and associated metallogenesis (July 22–24, 2003: Macquarie University, Sydney, Australia), pp 43–45Google Scholar
  11. Cuenot N, Dorbath C, Dorbath L (2008) Analysis of the microseismicity induced by fluid injections at the EGS site of Soultz-sous-Forêts (Alsace France): implications for the characterization of the geothermal reservoir properties. Pure Appl Geophys 165:797–828CrossRefGoogle Scholar
  12. Dash ZV, Murphy HD, Cremer GM (1981). Hot dry rock geothermal reservoir testing: 1978–1980. Los Alamos National Laboratory Report LA-9080-SRGoogle Scholar
  13. Dehkhoda S, Fairhurst C (2017) Rapid excavation and tunneling techniques. Hydraul Fract J 4(1):101–108Google Scholar
  14. Deichmann N, Giardini D (2009) Earthquakes induced by the stimulation of an enhanced geothermal system below Basel (Switzerland). Seismol Res Lett 80(5):784–798CrossRefGoogle Scholar
  15. Deichmann N, Kraft T, Evans KF (2014) Identification of faults activated during the stimulation of the Basel geothermal project from cluster analysis and focal mechanisms of the larger magnitude events. Geothermics 52:84–97CrossRefGoogle Scholar
  16. Duan K, Ji YL, Xu NW, Wan ZJ, Wu W (2019). Excavation-induced fault instability: possible causes and implications for seismicity. Tunnelling and underground space technology, 92, Article 103041Google Scholar
  17. Ernest LM, Roy B, Mitch S, Stephen O, Julian B, Bill S, Hiroshi A (2007) Induced seismicity associated with enhanced geothermal systems. Geothermic 36:185–222CrossRefGoogle Scholar
  18. Fairhurst C (2017) Some challenges of deep mining. Engineering 3(4):527–537CrossRefGoogle Scholar
  19. Feng Y, Chen X, Xu XF (2014) Current status and potentials of enhanced geothermal system in China: a review. Renew Sustain Energy Rev 33:214–223CrossRefGoogle Scholar
  20. Garnish JD (1976) ‘Geothermal energy’: the case for research in the United Kingdom. Energy paper no. 9, Her Majesty’s Stationery Office, LondonGoogle Scholar
  21. Gaucher E, Schoenball M, Heidbach O, Zang A, Fokkerc PA, van Wees J-D et al (2015) Induced seismicity in geothermal reservoirs: a review of forecasting approaches. Renew Sustain Energy Rev 52:1473–1490CrossRefGoogle Scholar
  22. Ghassemi A (2012) A review of some rock mechanics issues in geothermal reservoir development. Geotech Geol Eng 30:647–664CrossRefGoogle Scholar
  23. Goel RK, Singh B, Zhao J (2012) Underground Infrastructures: planning, design, and construction. Butterworth-Heinemann, OxfordGoogle Scholar
  24. Goldstein BA, Hill AJ, Long A, Budd AR, Ayling B, Malavazos M (2009) Hot rocks down under-evolution of a new energy industry. Geotherm Resour Counc Trans 33:185–198Google Scholar
  25. Guglielmi Y, Cappa F, Avouac JP, Henry P, Elsworth D (2015) Seismicity triggered by fluid injection-induced aseismic slip. Science 348(6240):1224–1226CrossRefGoogle Scholar
  26. Kang JQ, Zhu JB, Zhao J (2019) A review of mechanisms of induced earthquakes: from a view of rock mechanics. Geomech Geophys Geonergy Georesour. CrossRefGoogle Scholar
  27. Laughlin AW, West FG (1976) The Zuni Mountain, New Mexico, as a potential dry hot rock geothermail energy site. Los Alamos Scientific Laboratory report, LA-6197-MSGoogle Scholar
  28. Li M, Lior N (2015) Energy analysis for guiding the design of well systems of deep enhanced geothermal systems. Energy 93:1173–1188CrossRefGoogle Scholar
  29. Ma T, Chen P, Zhao J (2016) Overview on vertical and directional drilling technologies for the exploration and exploitation of deep petroleum resources. Geomech Geophys Geoenergy Georesour 2(4):365–395CrossRefGoogle Scholar
  30. Matsunaga I, Niitsuma H, Oikaya Y (2005) Review of the HDR development at Hijiori Site, Japan. In: Proceedings world geothermal congress (April 24–29, 2005: Antala, Turkey), pp 3861–3865Google Scholar
  31. Olasolo P, Juárez MC, Morales MP, D’Amico S, Liarte IA (2016) Enhanced geothermal systems (EGS): a review. Renew Sustain Energy Rev 56:133–144CrossRefGoogle Scholar
  32. Parker R (1999) The Rosemanowes HDR project 1983–1991. Geothermics 28:603–615CrossRefGoogle Scholar
  33. Perera MSA, Ranjith PG, Choi SK, Airey D (2011) The effects of sub-critical and super-critical carbon dioxide adsorption-induced coal matrix swelling on the permeability of naturally fractured black coal. Energy 36:6442–6450CrossRefGoogle Scholar
  34. Potter RM, Smith MC, Robinson ES (1974) Method of extracting heat from dry geothermal reservoirs. U.S. patent No. 3,786,858Google Scholar
  35. Ranjith PG, Zhao J, Ju MH, Radhika VS, De Silva RVS, Rathnaweera TD, Bandara AKMS (2017) Opportunities and challenges in deep mining: a brief review. Engineering 3(4):546–551CrossRefGoogle Scholar
  36. Rybach L, Bodmer Ph, Pavoni N, St Mueller (1978) Siting criteria for heat extraction from hot dry rock: applocation to Switzerland. Pure Appl Geophys 116:1211–1224CrossRefGoogle Scholar
  37. Tang CA, Zhao J, Wang SJ (2016) Conceptual model of Enhanced Geothermal System based on excavation technology (EGS-E). In: International geotechnics symposium cum international meeting of CSRME 14th Biennial National CongressGoogle Scholar
  38. Terakawa T, Miller SA, Deichmann N (2012) High fluid pressure and triggered earthquakes in the enhanced geothermal system in Basel, Switzerland. J Geophys Res 117:B07305CrossRefGoogle Scholar
  39. Wallroth T, Eliasson T, Sundquist U (1999) Hot dry rock research experiments at Fjällbacka, Sweden. Geothermics 28:617–625CrossRefGoogle Scholar
  40. Zang A, Stephansson O, Stenberg L, Plenkers L, Specht S, Milkereit C, Schill E, Kwiatek G, Dresen G, Zimmermann G, Dahm T, Weber M (2017) Hydraulic fracture monitoring in hard rock at 410 m depth with an advanced fluid-injection protocol and extensive sensor array. Geophys J Int 208:790–813CrossRefGoogle Scholar
  41. Zhao J (1987). Experimental studies of the hydro-thermo-mechanical behaviour of joints in granite. Ph.D. thesis, Imperial College LondonGoogle Scholar
  42. Zhao J (1994) Geothermal testing and measurements of rock and rock fractures. Geothermics 23(3):215–231CrossRefGoogle Scholar
  43. Zhao J (1996) Construction and utilization of rock caverns in Singapore part A: the Bukit Timah granite bedrock resource. Tunn Undergr Sp Technol 11:65–72CrossRefGoogle Scholar
  44. Zheng YL, Zhang QB, Zhao J (2016) Challenges and opportunities of using tunnel boring machines in mining. Tunn Undergr Sp Technol 57:287–299CrossRefGoogle Scholar

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Authors and Affiliations

  1. 1.Department of Civil EngineeringMonash UniversityClaytonAustralia
  2. 2.State Key Laboratory of Coastal and Offshore EngineeringDalian University of TechnologyDalianChina
  3. 3.Institute of Geology and GeophysicsChinese Academy of SciencesBeijingChina

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